The resistance in rowing is due to the drag of the water moving over the hull of the boat.
By the laws of hydrodynamics, this resistance/drag varies to thecube of the velocity/speed.
The rule of cubes therefore dictates that a doubling of the speed of the boat will require an eight-fold increase in resistance.
Like rowing, the WaterFlywheel’s resistance is increased by increasing speed. If you want more resistance then try to go faster. The outcome is that the resistance when rowing is infinite and infinitely variable.